Spark-plug.



' STATES PATENT FFICE.

WM'Y FAJWELL, 0F BOSTON, MASSACHUSETTS, ASSIGNOR 0F ONE-HALF TG CHARLES H. TBAISER, OF BOSTON, MASSACHUSETTS.

SPARK-PLUG.

senese.

Specification of Letters Patent.

Patented Jan. 17, 1911.

Application filed January 24, 1910. Serial No. 539,690.

To all whom it may concern:

Be it known that I, WRAY FALwnLL, a citizen of the United States, residing at Boston, in the county of Sufolk and State of Mas-- sachusetts, have invented certain new and useful Im rovements in Spark-Plugs, of which the ollowing is a specification.

My invention relates to removable sparkplugs for internal combustionengines, and its objects are to provide a better means of insulation between the electrodes, to permit greater freedom of movement of the grounded electrode without removing it from the devices holding the same, to employ spring actuated means in locking .the `grounded electrode to said holding devices, to completely obstruct the escape o the combustion gases, to better secure and protect the insulation, to prevent the over heating of the lug, and to simplify and render more efllective lthe operation of lthe several parts. j My invention/consists of a spark lug having a grounded shell-electrode an an electrode stein located within the same and eectually insulated therefrom a holder having a 4recess for receiving and holding'said shell-electrode, an open resilient ring resting upon lan inclined seat formed at the bottom of said recess, the shell-electrode having `Aan annular projection shaped to come in close'oontact with said seat and normally engaging the same below said ring, and a lock-nut threaded to engage the top of said holder, the lower end of' said lock-nut extending downwardly into said recess and forcing the ring into close contact with the uper face of said projection.

y invention further consists in constructing the handling cap of greater longitudinal dimensions than heretofore and in providing air spaces between the wall of said cap and the adjacent surface of the plug.

My invention further consists in constructingV the insulation sleeve with an enlargement thereon, which enlargement is confined in a recess formed within the grounded electrode-shell and secured to the smne by a collar, the other portions of the said sleeve having air spaces between the same and the grounded electrode.

lilly invention further consists in other improvements and modications more particularly pointed out and claimed in the 'following specification.

` 2, showing the I attain the several objects above set forth by the construction illustrated in the accompanying drawing, in which similar numerals of designation refer to similar parts throughout the several views.

Figure l. is a side elevation of my iinprofved spark plug and holder therefor; Fig. 2. is a vertical section of the same; Fig. 3. is an enlargement of the lower portion of Fig. spark-plug removed, and the position assumed by the locking ring when' the lock-nut is released; Fig. 4. is a view of the locking ring; Fig. 5. is a vertical section showing a modification of the lock-nut, the lower end of which is shown split into downwardly extending arms; Fig. 6. is a View of the 4lock-'nut shown in Fig. 5 looking from below. Fig. 7 is a vertical section of the holder and adjacent parts showing the use vof the modification shown in Figs. 5 and 6. l Reference is hereby made to the drawing, in which the cent/ral electrode stem 8 composed of sleeve 9 of insulating material which is preferably the substance now on the market called Isolit To secure the said insulating-sleeve 9, I construct the same with the 1 annular enlargement 10, which is shaped to engage within an annular recess formed in the outer or grounded electrode-shell 11, said recess terminating at the bottom thereof in a seat which engages with the base of said enlargementl and firmly holds the same in proper relation. The collar l12, is threaded to engage with the inner surface of the shell electrode, and to be turned down upon the top of said enlargement as shown, a small air space, however, being left between the inner surface of said collar and the outer surface of the insulation. At the base of said insulating-sleeve and integraly therewith is the downwardly projecting dan e 13, which is shaped to leave a considerab e space between the same and the grounded electrode, and is formed to have the recess 14, the top of which is shaped to receive and hold the head l5 at the lower end of the electrode stem 8 and prevent its upward movement. To the head 15 is affixed in any suitable manner the shank of the sparking terminal 16, the upper half of which shank flange 13 having considerthe two. The lower part the terminal point 17 is indorsed by the able space between of said shank bearing any suitable substance is for the 'greater portion thereof inclosed by a thick I mount the cap 18, formed of wood liber or other material which is both a good in-y sulator and a poor `conductor of heat, upon the upper part of the stem 8, the edgesof'said cap extending downwardly to protect the exposed portion of the insulation and being separated therefrom by a narrow air space, which serves to cool the cap and prevent its becoming heated. Above the cap 18, upon the screw threaded end of said stem 8 are also mounted the washer 19, the binding nut 2O and the thumb screw 21 for the purpose of aording a binding post for electrical connection to the wire from the generator.

All of the above description applies'to the spark-plug as a whole, which is complete in itself and is designed to be readily removed from the combustion chamber or installed therein without disturbing the relation of the electrodes. For. the purpose of attaching the said spark plug, to the combustion chamber, I employ a holder 22 which is formed with a screw threaded base for the purpose of engaging with a screw threaded orifice in said chamberl (not shown) and to be firmly secured. therein, such engagement being eliected by means of a wrench applied to the polygonal surface 23 formed on the exterior of said holder. The interior of said holder is made hollow for the purpose of permitting the insertion of the spark-plug, so that the ends of the' electrodes shall be in proper position in the combustion `cham ber. For the purpose of plug, I form the exterior of said plug with an annular projection 24C and an annular recess 25 immediately above the same, said projection 24 engaging with the lower part of the inclined seat 26. Above the said projection and in contact with the upper part of said inclined seat li locate the open ring 27 -composed of metal of such resilience as to cause the same to seek the top of said inclined seat when not acted upon by the lower end of the locking nut 28, which nut is threaded t0 engage with the recess in said holder at the upper part thereof. See Fig. 3.), To in'- sert the spark plug within said holder, the ring 27 is first placed within the same upon the top of the inclined seat 26; the lock nut 28 is then placed in proper position and turned down until the lower end of said nut is nearly in contact with said ring. The

plug may then be inserted without ditculty through the nut and ring and the projection 2% caused to rest upon the inclined seat 26.

securing the said i Upon again turning the lock-nut 28, the endot' the same comes into contact with said ring and forces it downwardly against said projection 24 and into the recess 25, where the said ring 27 rests equally upon said projection and inclined seat, Vthe diameter of said ring being made great enough for this purpose. When in such position the ring securely holds the spark plug within its holder, and it is only by loosening the locking nut 28 and permitting the ring to ascend to the top of the .inclined seat that the plug can be removed fromsaid holder.

In Figs. 5, 6 and V7, I have shown a modiication of the lresilient spring holding means, in that I have employed for this purpose the lower end of the locking nut 28,. the said end being extended somewhat lower and beingsplit into the resilient arms 29, the extremity of each of which is shaped to engage with both the said projectien and inclined seat as shown in Fig. 7, and to securely lock the said plug to the holder.

One important improvement covered by my invention is the new arrangement .of parts permitting the spark-plug to be turned completely around in its yholder or to any part of the circumference of the same witho ut removing the plugfrom the holder. To accomplish said result it is only necessary to partially loosen the locking-nut 28, when the ring will retreat suiiiciently from its engagement with the projection 24, to permit the plug to be turned as described. So far as I am aware no prior device discloses this feature and I desire to cover this improvement i'n the broadest manner possible, though I do not desire to limit my broad invention to include merely this feature in combination with other parts of'my improved construction.` Neither do I desire to limit my invention to other exact and specific parts, it being obvious Ithat modification and changes could be ed'ected in my device without departing from the spirit of my invention. j What I claim and desire to secure by Letters Patent is,h

1. In a spark plug, a metallic shell electrede, a projection upon the exterior of said electrode, a hollow metallic holder shaped to receive and hold said electrode and the projection thereon, combined with a'hloclr nut and a metallic s ring coperating therewith and engaging .wlth said projection and locking the same within vsaid holdern 2. In a spark plug, a metallic shell electrode, an annular projection upon said electrode, a hollow metallic holder shaped to receive said electrode and having an annular recess therein, the bottom of said recess terminating in an inclined seat shaped to engage said projection, combined with a lock nut and a metallic packing coperating therewith and engaging withboth said seat @emez and projection and locking the saine together.

il. ln a spark plug, a metallic shell electrode, an annular projection upon said holder7 a hollow metallic holder Shaped to receive said electrode and having therein an annular recess. the. bottoni of said recess terminating in an inclined seat shaped -toengagfe Saidprojection, a metallic packing ring engaging w ith both said Seat and projection, and a locking nut threaded t/o engage said recess and to je with said ring and loci; the same ag st said seat and projection.

l. ln a` spark plug, a metallic shell electrode, an annular projection upon said holder, a hollow metallic holder shapedto receive said electrode and haring therein an annular recess, the bottom of said recess terminating: in an inclined seaft shaped to 1 enga ge saidprojection, a resilient lnetalring l engaging with both said seat and projection, j and a nut threaded to engage said recess and to engage with said means and lock the same j against Said seat and projection.

Iln testimonyv whereof I have affixed my signature. in presence of two Witnesses.

VRAY FALVELL.

'v'tnesses Joux Dtrr. E. N. Courts. 

